1. Field of the Invention
This invention deals with fiber optic switches, more specifically with packaging for fiber optic switches.
2. Background of the Invention
Switching for fiber optics has previously largely been done in the optoelectronic realm. The fiber optics, which are purely optical, have been coupled with circuitry that allows the switching to be done electrically, and then the signals are converted back to optical for transmission. This is slower and more complicated than using purely optical techniques, where the switching is done optically.
Purely optical switching has been achieved in many ways. One of which is accomplished by use of a liquid crystal (LCD) spatial light modulator to transmit or not transmit light through the switching network resulting in the switching operation. This method has a slow response time and there is the difficulty of alignment.
Another of these methods involves the use of a electro-optic crystalline material such as LiNbO.sub.3. But, LiNbO.sub.3 waveguide switches have been limited to use with a single-mode fiber. These switches are also currently polarization dependent although work is underway to eliminate this dependency.
Yet another of the ways to achieve optical switching is with the use of the deformable mirror device (DMD) spatial light modulator. The DMD operates in the reflective mode. The DMD is controlled to reflect light by individually controlling each member of an array of mirrors. There exist other patents that have issued or have been filed that apply to this concept. They are U.S. Pat. Nos. 4,811,210, 4,859,012, 4,856,863 which are incorporated by reference herein.
Connectors designed to hold fibers and DMDs in relative alignment previously have been made out of various materials such as aluminum and delrin. These materials are machined or molded to obtain the final desired shape. The fiber arrays are held at an angle relative to each other and the end package.
Many limitations of this approach exist, including manufacturability, cost, size, and complexity. The manufacturing necessary, either machining or molding introduces inaccuracy and instabilities in the final package. This manufacturing process is also labor intensive and therefore expensive.
The size of the connector required to accommodate two or more fiber arrays is relatively large. Further more, to achieve the desired angles relative to the other fiber arrays and the end package, the fibers must be supported as they exit the back of the arrays. This occupies still more space, and leads to switch installation complexity. Also, connectors of the necessary size and weight are prone to instabilities from vibrations and thermal effects.
Additionally, the fact that the fiber ends are held up far above the plane at which the switching occurs introduces a strong possibility of accidental physical interaction with a part of the switch, resulting in operational instability.